a(n) = A353791(sigma(A003961(n))), where A353791(n) = A003958(n) * A064989(n).

Terms

a(0) =1a(1) =1a(2) =4a(3) =132a(4) =1a(5) =4a(6) =4a(7) =12a(8) =870a(9) =1a(10) =30a(11) =528a(12) =16a(13) =4a(14) =4a(15) =4900a(16) =12a(17) =870a(18) =4a(19) =132a(20) =16a(21) =30a(22) =48a(23) =48a(24) =1224a(25) =16a(26) =528a(27) =528a(28) =1a(29) =4